Voxel-based morphometric MRI post-processing in MRI-negative focal cortical dysplasia followed by simultaneously recorded MEG and stereo-EEG

We aim to report on the usefulness of a voxel-based morphometric MRI post-processing technique in detecting subtle epileptogenic structural lesions. The MRI post-processing technique was implemented in a morphometric analysis program (MAP), in a 30-year-old male with pharmacoresistant focal epilepsy and negative MRI. MAP gray-white matter junction file facilitated the identification of a suspicious structural lesion in the right frontal opercular area. The electrophysiological data by simultaneously recorded stereo-EEG and MEG confirmed the epileptogenicity of the underlying subtle structural abnormality. The patient underwent a limited right frontal opercular resection, which completely included the area detected by MAP. Surgical pathology revealed focal cortical dysplasia (FCD) type IIb. Postoperatively the patient has been seizure-free for 2 years. This study demonstrates that MAP has promise in increasing the diagnostic yield of MRI reading in challenging patients with "non-lesional" MRIs. The clinical relevance and epileptogenicity of MAP abnormalities in patients with epilepsy have not been investigated systematically; therefore it is important to confirm their pertinence by performing electrophysiological recordings. When confirmed to be epileptogenic, such MAP abnormalities may reflect an underlying subtle cortical dysplasia whose complete resection can lead to seizure-free outcome.     

Voxel-based 3D MRI analysis helps to detect subtle forms of subcortical band heterotopia

PURPOSE: To evaluate the potential diagnostic value of a novel magnetic resonance image (MRI) postprocessing technique in subtle forms of subcortical band heterotopia (SBH). The method was introduced to improve the visualization of blurred gray-white matter junctions associated with focal cortical dysplasia but was found to be applicable also to SBH. METHODS: In the voxel-based MRI analysis presented here, T1-weighted MRI volume data sets are normalized and segmented using standard algorithms of SPM5. The distribution of gray and white matter is analyzed on a voxelwise basis and compared with a normal database of 150 controls. Based on this analysis, a three-dimensional feature map is created that highlights brain areas if their signal intensities fall within the range between normal gray and white matter and differ from the normal database in this respect. The method was applied to the MRI data of 378 patients with focal epilepsy in three different epilepsy centers. RESULTS: SBH was diagnosed in seven patients with five of them showing subtle forms of SBH that had gone unrecognized in conventional visual analysis of MRI and were only detected by MRI postprocessing. In contrast to distinct double cortex syndrome, these patients had partial double cortex with SBH mostly confined to posterior brain regions. CONCLUSIONS: The results of this study suggest that a considerable part of cases with SBH might remain unrecognized by conventional MRI. Voxel-based MRI analysis may help to identify subtle forms and appears to be a valuable additional diagnostic tool in the evaluation of patients with cryptogenic epilepsy.     

Texture analysis and morphological processing of magnetic resonance imaging assist detection of focal cortical dysplasia in extra-temporal partial epilepsy.

In many patients, focal cortical dysplasia (FCD) is characterized by minor structural changes that may go unrecognized by standard radiological analysis. To increase the sensitivity of magnetic resonance imaging (MRI) for the detection of subtle lesions of FCD, we developed voxel-based image postprocessing methods, including first-order texture analysis and morphological processing modeled on known MRI features of FCD. We selected 16 patients with histologically proven FCD. Image processing features were calculated over a neighborhood for each voxel in the three-dimensional T1-weighted MRI. Three feature maps were generated: (1) gray matter thickness map to model cortical thickening, (2) gradient map to model blurring of the gray matter-white matter junction, and (3) relative intensity map to model the hyperintense signal within the lesion. Two observers detected lesions on conventional MRI in 8/16 and on ratio maps in 14/16 patients. Sensitivity was 87.5% (14/16) for the ratio maps compared to 50% (8/16) for MRI (p < 0.003). Specificity was 95% (19/20) for ratio maps and 100% (20/20) for MRIs. Cohen's kappa was 0.53 for MRIs, indicating moderate agreement, and 0.83 for ratio maps, indicating strong agreement beyond chance between the 2 observers. The image-processing methods developed in this study improve visual detection of FCD, even in cases where no lesion is obvious on MRI. These techniques could increase the number of patients with partial epilepsy who could benefit from surgery.     

Different presurgical characteristics and seizure outcomes in children with focal cortical dysplasia type I or II

Purpose:   Cortical dysplasia (FCD) is a frequent cause of epilepsy in childhood. Two major pathological variants are distinguished, FCD type I and II. The aim of the study was to characterize differences between FCD type I and II with respect to imaging and EEG findings, clinical and neuropsychological presentations, and surgical outcome.
Methods:   Forty children with refractory epilepsy and histopathologically confirmed FCD were retrospectively analyzed. FCD type I was identified in 24 and FCD type II in 16 patients.
Results:   Characteristic MRI abnormalities in FCD type I included subtle white matter signal changes and regional reduction of the white matter volume. Typical MRI findings in FCD type II were increased cortical thickness, transmantle sign, gray-white matter junction blurring, fluid-attenuated inversion recovery (FLAIR) and proton density (PD) gray matter signal changes as well as T1w, and PD white matter signal changes. Continuous EEG slowing was significantly more common in patients with FCD type I. Children with FCD type I presented with lower levels of intelligence and were suffering more often from maladaptive behavior and behavioral disorders. Surgical outcome was significantly worse in the FCD type I group (seizure freedom was achieved in 21% FCD type I patients and in 75% FCD type II subjects, p < 0.001).
Conclusions:   Clinically important differences were found in children with distinct histopathological subtypes of FCD. Due to prominent neuropsychological deficits and worse seizure outcome, treatment strategies in FCD type I are more challenging than previously reported and these children should be recognized and specifically addressed within the incoherent group of patients with malformative brain disorders.     

Comparison of MRI features and surgical outcome among the subtypes of focal cortical dysplasia

PurposeFocal cortical dysplasia (FCD) is the most common pathological diagnosis in patients who have undergone surgical treatment for intractable neocortical epilepsy. However, presurgical identification of MRI abnormalities in FCD patients remains difficult, and there are no highly sensitive imaging parameters available that can reliably differentiate among FCD subtypes. The purpose of our study was to investigate the surgical outcome in FCD patients with identifiable MRI abnormalities and to evaluate the prognostic role of the various MRI features and the characteristics of FCD pathology.MethodsWe retrospectively recruited epilepsy patients who had undergone surgical treatment for refractory epilepsy with focal MRI abnormalities and the pathological diagnosis of FCD. We evaluated the surgical outcome according to the pathological subtypes, and studied the prognostic roles of various MRI features. We used recently proposed three-tiered FCD classification system which included FCD type III when FCD occurs in association with other potentially epileptogenic pathologies.ResultsA total of 69 patients were included, and 68.1% of patients became seizure free. Patients with FCD type III had a lower chance for achieving seizure freedom (7/15) than in patients with isolated FCD (FCD types I and II) (40/54, p = 0.044). Cortical thickness and blurring of gray–white matter junction were more common in isolated FCD than in FCD type III, but most MRI features failed to differentiate between FCD types I and II, and only the transmantle sign was specific for FCD type II. We failed to find a prognostic value of specific MRI abnormalities of prognostic value in terms of post-epilepsy surgery outcome in FCD patients.ConclusionsOur study showed that patients with FCD III have poor surgical outcome. Typical MRI features of isolated FCD such as cortical thickness and blurring of gray–white matter junction were less common in FCD type III and only transmantle sign was helpful in differentiating between FCD types I and II.     

Taylor-type focal cortical dysplasia in infants: some MRI lesions almost disappear with maturation of myelination

Identification of focal cortical dysplasia (FCD) on magnetic resonance (MR) images of young children with refractory focal epilepsy is important, as surgical resection may offer improvement of seizure control and subsequent developmental progress. However, the MR appearances of malformations of cortical development may change during brain maturation. We report 4 children with refractory focal epilepsy, whose MR images in infancy showed localized cortical and subcortical signal abnormalities (hypointense on T(2)-weighted and hyperintense on T(1)-weighted images), suggestive of abnormal cortical development. The visibility of these lesions was significantly reduced on later MR images. Subtle blurring of the gray-white matter junction in these areas was the only indicator of cortical abnormality in 3 patients, which was recognized only after comparison with earlier images. Taylor-type FCD was subsequently confirmed in all patients, following surgical cortical resection of the lesions. MR images performed early within the first year of life in children with epilepsy are important to identify areas of FCD. The appearances of FCD on later scans can be very subtle escaping recognition, and conclusions may be misleading with respect to diagnosis and appropriateness of surgical treatment.     

In vivo profiling of focal cortical dysplasia on high-resolution MRI with computational models

PURPOSE: On MRI, focal cortical dysplasia (FCD) is characterized by a combination of increased cortical thickness, hyperintense signal within the dysplastic lesion, and blurred transition between gray and white matter (GM-WM). The visual identification of these abnormal characteristics may be difficult, and it is unclear to what degree these features occur among different FCD lesions. Our purpose was to investigate the pattern of occurrence of abnormal MRI characteristics in FCD by using a set of computational models and to generate quantitative lesion profiling. METHODS: A set of voxel-wise operators was applied to high-resolution 3D T1-weighted MRI in 23 patients with histologically proven FCD and 39 healthy controls, creating maps of GM thickness, maps of relative intensity highlighting areas with hyperintense signal, and maps of gradient magnitude modeling the GM-WM transition. All FCD lesions were segmented manually on the T1-weighted MRI. RESULTS: FCD volumes ranged from 734 mm3 to 80,726 mm3 (mean, 8,629 mm3 +/- 16,238). The manually segmented FCD lesions were used to estimate features in the lesional area and to determine possible local variations of each feature by means of a histogram. In 78% of the patients, FCD lesions were characterized by simultaneous GM thickening, hyperintense signal, and blurring of the GM-WM transition. Moreover, in all patients, the FCD lesion had at least two of these three characteristics. CONCLUSIONS: The three features occurred regardless of the lesion volume, and they characterized not only large FCD lesions, but also subtle ones that had been overlooked by conventional radiologic inspection before surgery.     

Prospective magnetic resonance imaging identification of focal cortical dysplasia,including the non—balloon cell subtype

The purpose of this study was to determine the role of high-resolution T2-weighted fast multiplanar inversion-recovery (FMPIR) magnetic resonance (MR) imaging in detecting and delineating microscopic focal cortical dysplasia (FCD). We performed MR scans with FMPIR on 42 patients with suspected neocortical epilepsy. Ten MR studies were read prospectively as showing FCD; these case histories, electroencephalographic studies, and neuroimaging data were reviewed. Eight of these patients subsequently underwent focal cortical resection guided by intraoperative electrocorticography. The MR findings were correlated with pathological findings in these 8 patients. For purposes of radiological-pathological correlation, the FCD lesions were divided into two classes. Radiological classification was based on the absence (type A) or presence (type B) of T2 prolongation of the subcortical white matter. Pathological grading as type I or type II was based on a previously described pathological grading system. Specific MR findings associated with FCD included focal blurring of the gray-white matter interface (n = 9), thickening of the cortical ribbon (n = 7), and T2 prolongation of the subcortical white matter (n = 4). In 3 patients, the only MR finding that suggested FCD was localized blurring of the gray-white matter junction. In 2 of these 3 patients, the MR diagnosis of FCD could be made only by FMPIR. FCD was confirmed histologically in 7 of 8 patients, with insufficient tissue for complete histopathological evaluation in 1 case. Radiological classification of FCD agreed with pathological classification in 5 of 7 cases. Correlation of MR findings with intraoperative electrocorticography results indicated that the MR study localized the epileptogenic lesion correctly in 8 of 8 cases. Scalp ictal electroencephalographic studies localized the epileptogenic lesion in 5 of 8 cases; positron emission tomographic scans were focally abnormal in 3 of 3 cases. FMPIR MR imaging permitted accurate diagnosis and localization of FCD in all patients with pathologically proved FCD. MR identification of FCD aided presurgical planning and intraoperative management of these patients.     

Detection and localization of focal cortical dysplasia by voxel-based 3-D MRI analysis

PURPOSE: Focal cortical dysplasia (FCD) is a frequent cause of partial epilepsy. Its diagnosis by visual evaluation of magnetic resonance images (MRIs) remains difficult. The purpose of this study was to apply a novel automated and observer-independent voxel-based technique for the analysis of 3-dimensional (3-D) MRI to detect and localize FCD. METHODS: The technique was based on algorithms of the SPM99 software and included the spatial normalization of 3-D MRI data sets to a common stereotaxic space and the segmentation of cortical grey matter. The resulting data sets represented grey-matter density maps where each voxel encoded the grey-matter concentration at the corresponding position in the original MRI. A normal database was set up by calculating and averaging the grey-matter density maps of 30 healthy volunteers. The MRI data sets of seven epilepsy patients with FCD were evaluated retrospectively for dysplastic lesions by voxelwise subtraction of the mean grey-matter density map of the normal database and searching automatically for local and global maxima in the resulting data set. RESULTS: In all patients, the results of voxel-based 3-D MRI analysis corresponded both to the location of the dysplastic lesions in conventional MRI and to seizure semiology and EEG findings. In one case, surgery was performed, and the diagnosis FCD was supported by histology. CONCLUSIONS: The technique of voxel-based 3-D MRI analysis and comparison with a normal database seems to provide a valuable additional screening tool for the detection of FCD.     

高分辨核磁共振成像在预测儿童局灶性皮质发育不良手术效果中的价值

目的 探讨高分辨核磁共振成像(MRI)在儿童局灶性皮质发育不良(Focal cortical dysplasia,FCD)手术中的效果及价值.方法 回顾性分析2013年7月-2018年7月于山东大学齐鲁儿童医院经手术病理证实的143例FCD患儿的MRI及临床资料,年龄5月龄～12.5岁,既往无治疗史,分析其MRI征象:...     

高分辨MRI在Ⅰ型局灶性皮质发育不良患儿术前评估中的应用

目的 探讨高分辨MRI成像在儿童Ⅰ型局灶性皮质发育不良(FCD)术前评估中的价值.方法 回顾性分析52例经病理学证实的FCD Ⅰ型患儿的MRI及相关临床资料,比较高分辨成像与MRI常规序列对Ⅰ型FCD各主要MRI征象(局灶性灰白质分界模糊、局灶性皮质结构异常、白质异常信号灶及局限性脑叶萎缩/发育不全)的检出率,以及对病...     

Voxel-based morphometry in the detection of dysplasia and neoplasia in childhood epilepsy: Limitations of grey matter analysis

The purpose of this exploratory investigation was to evaluate voxel-based morphometry (VBM) in detecting lesions underlying childhood epilepsy, and to establish the optimal image processing and statistical parameters in this context. The patients were 16 children (10 boys) aged 5.9 to 15.2 years (mean 11.3 years) with epilepsy and focal cortical dysplasia (FCD) or neoplasia. The control group comprised 24 normal children (12 boys), age matched to the patients. MRI volumes were spatially normalised to a custom template and segmented into grey matter (GM) and white matter. Using statistical parametric mapping, the GM segment from each patient was then contrasted with the mean GM segment of the control group utilising different VBM post-processing methods. Maps showing increased/decreased areas of GM concentration or volume were generated and compared with visually identified lesions. The results indicated that conservative VBM parameters of linear normalisation with no modulation produced the highest rates of lesion detection, which were identical for FCD and neoplasia at 5/8 lesions. These preliminary data suggest that VBM analysis of GM using conservative parameters can usually detect FCD and neoplasia in the MRI of children with epilepsy, but sensitivity may be inadequate for routine clinical application. Further refinement of the technique may be necessary.     

Neuroimaging of Focal Cortical Dysplasia

Focal cortical dysplasia (FCD) is a common cause of pharmacoresistant epilepsy that is amenable to surgical resective treatment. The identification of structural FCD by magnetic resonance imaging (MRI) can contribute to the detection of the epileptogenic zone and improve the outcome of epilepsy surgery. MR epilepsy protocols that include specific T1 and T2 weighted, and fluid-attenuated inversion recovery (FLAIR) sequences give complementary information about the characteristic imaging features of FCD; focal cortical thickening, blurring of the gray-white junction, high FLAIR signal, and gyral anatomical abnormalities. Novel imaging techniques such as magnetic resonance spectroscopy (MRS), magnetization transfer imaging (MTI), and diffusion tensor imaging (DTI) can improve the sensitivity of MR to localize the anatomical lesion. Functional/metabolic techniques such as positron emission tomography (PET), ictal subtraction single photon emission computed tomography (SPECT), functional MRI (fMRI), and magnetic source imaging (MSI) have the potential to visualize the metabolic, vascular, and epileptogenic properties of the FCD lesion, respectively. Identification of eloquent areas of cortex, to assist in the surgical resection plan, can be obtained non-invasively through the use of fMRI and MSI. Although a significant number of FCD lesions remain unidentified using current neuroimaging techniques, future advances should result in the identification of an increasing number of these cortical malformations.     

Neuropathologic measurements in focal cortical dysplasias: validation of the ILAE 2011 classification system and diagnostic implications for MRI

Focal cortical dysplasias (FCD) which represent a composite group of cortical malformations are increasingly recognized as morphological substrate for severe therapy-refractory epilepsy in children and young adults. However, presurgical evaluation remains challenging as not all FCD variants can be reliably detected by high-resolution magnetic resonance imaging (MRI). Here, we studied a cohort of 52 epilepsy patients with neuropathological evidence for FCD using the 2011 classification of the International League against Epilepsy (ILAE) and systematically analysed those histopathologic features applicable also for MRI diagnostics. Histopathologic parameters included quantitative measurements of cellular profiles, cortical thickness, heterotopic neurons in white matter, and myelination that were compared between FCD subtypes and age-/localization-matched controls (n = 36) using multivariate analysis. Dysmorphic neurons in both FCD Type II variants showed significantly increased diameter of their cell bodies and nuclei. Cortical thickness was also increased with a distinct loss of myelin content specifying FCD Type IIb from IIa. The data further suggested that myelination deficits in FCD Type IIb result from compromised oligodendroglial lineage differentiation and we concluded that the "transmantle sign" is a unique finding in FCD Type IIb. In contrast, FCD Type Ia was characterized by a smaller cortical ribbon and higher neuronal densities, but these parameters failed to reach statistical significance (considering age- and location-dependent variability in controls). All FCD variants showed abnormal grey-white matter boundaries with increased numbers of heterotopic neurons. Similar results were obtained also at deep white matter location. Thus, many FCD variants may indeed escape visual MRI inspection, but suspicious areas with increased or decreased cortical thickness as well as grey-white matter blurring may be uncovered using post-processing protocols of neuroimaging data. The systematic analysis of well-specified histopathological features could be helpful to improve sensitivity and specificity in MRI detection during pre-surgical work-up of patients with drug-resistant focal epilepsies.     

Voxel-based morphometry in the detection of dysplasia and neoplasia in childhood epilepsy: combined grey/white matter analysis augments detection

PURPOSE: Analysis of grey matter on MRI utilising voxel-based morphometry (VBM) may have insufficient sensitivity for routine clinical application. The aim of this exploratory study was to evaluate combined analysis of grey and white matter using VBM for detecting focal lesions underlying childhood epilepsy, and to establish the optimal statistical parameters in this context. METHODS: The patients were 16 children (10 boys) aged 5.9-15.2 years (11.3+/-2.8 years; mean+/-S.D.) with epilepsy and focal cortical dysplasia (FCD) or neoplasia. The control group comprised 24 normal children (12 boys), age matched to the patients. VBM was used to spatially normalise MRI volumes to a custom template and segment them into grey matter (GM) and white matter (WM). The combined GM/WM segments from each patient were contrasted with the control group. Three different VBM post-processing techniques of combined GM/WM were evaluated along with GM-only analysis. Maps showing increased/decreased GM or GM/WM concentration were generated and compared with visually identified lesions. Rates of detection and true/false positives voxels were calculated. RESULTS: The GM-only lesion detection rate was equal for FCD and neoplasia at 5/8, whereas the best combined GM/WM technique detected 8/8 FCD and 6/8 neoplasia. The combined technique also produced a higher overall rate of true positives (87%) than GM-only (44%) with a similar low rate of false positives. CONCLUSIONS: These preliminary data suggest that VBM is ineffective for precise delineation of lesion margins, but could potentially be used to detect subtle dysplasia in MRI negative and equivocal cases.     

Epilepsy surgery in children with focal cortical dysplasia (FCD): results of long-term seizure outcome

The purpose of this study was to assess the effect of epilepsy surgery on seizure outcome in children and adolescents under 18 years with intractable epilepsy due to focal cortical dysplasia. We analysed clinical data, such as age at seizure onset, epilepsy course, localisation of focus from presurgical evaluation, MRI, tissue pathology and seizure outcome in 68 patients 6 months to 9 years after epilepsy surgery. Seizure outcome was classified according to the Engel classification. Mean age at seizure onset was 7 months, ranging from the first days of life to 7 years. All patients had medically intractable epilepsy. Localisation of the lesion was predominantly extratemporal: posterior (uni- or multilobar) 43 %, frontal without central region 26 %, multilobar involving central area 19 % and temporal in 12 %. MRI signs typically seen in cortical dysplasia (FCD) such as localised blurring of gray-white matter junction was found in 68 %, dysgyria in 62 %, thickening of the cortical ribbon in 46 % and T2 signal elongation of the subcortical white matter in 40 % of the patients' MRI. Age at surgery ranged from 5 months to 16 years; 14 patients were under 2 years when operated on. In 34 patients (6 patients under 3 years) subdural grid electrode evaluation was performed prior to surgery. Pathology revealed focal cortical dysplasia without balloon cells (type I) in 60 %, FCD of the balloon cell subtype (type II) in 40 % of the specimens. Postoperative complications were subdural hygroma in 5 and an increased motor deficit in 2 patients. Up to two years after epilepsy surgery 50 % of the children were seizure free (Engel class I), 10 % Engel class II, 33 % Engel class III and 7 % unchanged (Engel class IV). Long-term seizure outcome (> 3 years post surgery) in 32 patients showed similar results (class I 50 %, class II 19 %, class III 28 %, class IV 3 %). Complete resection of the dysplastic lesion was significantly correlated with favorable seizure outcome, whereas seizure outcome was not significantly different in patients with mild (type I) or balloon cell (type II) FCD. Children operated after 6 years of age had no better outcome than children operated in infancy or at preschool age. Epilepsy surgery resulted in good (class I and II) seizure control in 60 % of children with intractable epilepsy due to focal cortical dysplasia.     

Doublecortin expression in focal cortical dysplasia in epilepsy

Purpose: Doublecortin (DCX) is a microtubule‐associated protein with regulatory roles in radial and tangential migration of neurons during cortical development. In normal adult cortex there is restricted expression, and DCX is widely used as a marker of neurogenesis. Imperfect corticogenesis is thought to underpin many focal cortical pathologies in epilepsy surgical series, including focal cortical dysplasia (FCD). The aim was to study DCX expression patterns in such lesions compared to normal developing and mature cortex. Method: Cases of FCD types Ia (13) and IIb (4), pediatric hippocampal sclerosis (HS) (5), temporal lobe sclerosis (5), glioneuronal tumors (5), gray matter heterotopia (3), and control tissues (16) from a wide age range [20 gestational weeks (GW) to 85 years] were studied using immunohistochemistry to DCX. Results: In controls and all epilepsy cases, perinuclear labeling of small round cells (SRCs) and satellite perineuronal cells was observed in both postmortem and surgical tissues. In FCD Ia up to the age of 4 years, prominent DCX‐positive (DCX⁺), immature cells were present along the junction of layers I and II, with processes extending into the molecular layer. These cell types were not a significant feature in other pathologies, which showed multipolar DCX⁺ cells or labeling of dysmorphic cells throughout the cortex. Discussion: Persistent cellular DCX expression is confirmed in normal adult cortex. Characteristic expression patterns in layer II of FCD Ia could indicate delayed or abnormal cortical maturation rather than ongoing cytogenesis. This could be indicative of enhanced local cortical plasticity as well as a potential diagnostic feature of this type of pathology.     

Diffusion tensor imaging abnormalities in focal cortical dysplasia

PURPOSE: Focal cortical dysplasia (FCD) is one of the most common underlying pathologic substrates in patients with medically intractable epilepsy. While magnetic resonance imaging (MRI) evidence of FCD is an important predictor of good surgical outcome, conventional MRI is not sensitive enough to detect all lesions. Previous reports of diffusion tensor imaging (DTI) abnormalities in FCD suggest the potential of DTI in the detection of FCD. The purpose of this study was to study subcortical white matter underlying small lesions of FCD using DTI. METHODS: Five patients with medically intractable epilepsy and FCD were investigated. Diffusion tensor imaging images were acquired (20 contiguous 3 mm thick axial slices) with maps of fractional anisotropy (FA), trace apparent diffusion coefficient (trace/3 ADC), and principal eigenvalues (ADC parallel and ADC perpendicular to white matter tracts) being calculated for each slice. Region of interest analysis was used to compare subcortical white matter ipsilateral and contralateral to the lesion. RESULTS: Three subjects with FCD associated with underlying white matter hyperintensities on T2 weighted MRI were observed to have increased trace/3 ADC, reduced fractional anisotropy and increased perpendicular water diffusivity which was greater than the relative increase in the parallel diffusivity. No DTI abnormalities were identified in two patients with FCD without white matter hyperintensities on conventional T2-weighted MRI. CONCLUSIONS: While DTI abnormalities in FCD with obvious white matter involvement are consistent with micro-structural degradation of the underlying subcortical white matter, DTI changes were not identified in FCD lesions with normal appearing white matter.     

不同病理分型局部脑皮质发育不良的MRI研究

目的 探讨不同病理分型局部脑皮质发育不良(FCD)在MRI表现上的特点.方法 回顾性分析广州医学院第二附属医院自2006年5月至2010年6月收治的23例FCD患者资料.所有患者均经手术病理证实,按Palmini方法FCDⅠA、FCDⅠB、FCDⅡA、FCDⅡB4型,总结各类型患者MRI表现的特点.结果 23例患者中FCD Ⅰ A 2例,FeD Ⅰ B 6例,FCDⅡA 8例,FCDⅡB7例.FCDⅡ型中,有11例MRI表现为病灶Flair高信号,Ⅰ型中仅有2例,差异有统计学意义(P=0.039).而病灶T2高信号、白质内向脑室延伸带等表现虽然在Ⅰ、Ⅱ型间相差较大,但差异没有统计学意义(P=0.074、0.058).ⅡB型的MRI表现在灰白质分界不清、病灶T2高信号、脑沟加深、灰质增厚、白质内向脑室延伸带等方面均明显高于其他3型,差异有统计学意义(P<0.05).结论 不同病理分型FeD的MRI表现各有特点,特别是ⅡB型,其在MRI上的表现与其他3型明显不同,了解这些特点有助于FCD的早期诊断和术前评估.     

脑皮质发育不良继发顽固性癫痫的病理分型及手术治疗

目的 探讨局灶性脑发育不良(FCD)的临床特征、病理学、影像学的特点及手术疗效.方法 42例外科手术切除致痫灶并经病理证实为FCD的患者中,根据Palmini病理学分型进行分类,并对其临床特征、影像学特点及手术疗效进行回顾性分析.结果 42例患者中,按致痫灶部位分类颢叶24例、额叶14例、顶叶6例及枕叶3例,其中多脑叶5例.术前影像学检查阳性率62%.组织学分型FCDⅠA型9例,FCDⅠB型21例,FCDⅡA型5例,FCDⅡB型7例,其中以FCD Ⅰ B型最为常见,多位于颞叶且常伴有海马硬化.所有患者术后至少随访1年以上,癫痫术后治愈率FCD位于颞叶67%,颞叶以外43%(EngleⅠa).结论 FCD是难治性癫痫常见的病理学改变,其病理分型与临床特征和致痫灶部位存在相关性,为制定手术方案和判定手术效果提供了依据.